You don't.
Probably nobody told you so far, but applets are "dead technology". The only reason to do anything with Applets in 2016 is because you are working in some company that still uses them for some of their internal stuff. Then, and only then you should be spending your time on learning/programming applets. But in any other case, you would be wasting your time.
You see, browser like chrome have stopped supporting Java/applets quite some months ago.
Nobody does reasonable front work using applets any more. In other words: look into JavaScript or any of the huge frameworks around that. And figure how to use something like that instead of applets.